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Secrets in the Cinders
How Native Americans in the Southwest survived--and even profited from--an eleventh-century volcanic eruption.

This article first appeared in a different form in Archaeology, Volume 57 Number 2, March/April 2004.

Archaeologist Mark Elson and geomorphologist Kirk Anderson are studying  half-buried, scattered stones in a forest of ponderosa pines. Most of us would stroll by this spot without a second glance, but Elson and Anderson are using high-tech tools -- a computerized laser beam and a GPS -- to record the position of every stone. They are the remains of what was once a ten-room pueblo inhabited nine centuries ago, a pueblo whose walls contained mysterious volcanic rocks.
It is late May, and we're 40 miles from the nearest paved road, 15 miles north of the Grand Canyon, in a zone of remote forests and canyons known as the Arizona Strip. It's not yet 8 AM but it's already growing hot. The flies are beginning to buzz, and there's not the slightest trace of breeze.  
What drew us here were unusual chunks of brown stone, studded with bits of ancient pottery that an archaeologist discovered in the ruin in 1997. She assumed that a lightning blast had melted the ceramics to the rock and gave them to the Bureau of Land Management for storage. Four years later BLM archaeologist John Herron recognized the rocks as lava. He called Mark Elson.  
Elson, 47, has spent the last six years pondering the relationship of early Americans to volcanoes. The ancient people of the Southwest marveled at their power and splendor when they erupted; when their ashes cooled they planted corn in their cinders, and they even used their lava flows as canvas: a few miles from here is a wall of basalt with thousands of petroglyphs pecked into its surface, mysterious images of deer, snakes, sheep, hunters, suns, and swirling spirals. 
As Elson and Anderson survey, ceramics expert Terry Samples sits nearby on an upended plastic bucket, picking up pottery sherds that he found on the open ground. He notes their color and texture, then whacks them with a wrench and peers through a loupe at the freshly exposed surface to see the minerals in their clay. He quickly identifies their styles; I'm sitting beside him in the dust, keeping census on a tally sheet.
Yesterday the team found three more of the pottery-studded rocks in the ruin's fallen walls. Elson calls them “sherd rocks,” and believes they were made almost a millennium ago, when, a mile away, Little Springs Volcano erupted. The survey of the ruin and pottery may offer clues to who made the rocks and why. 
Elson has dark hair, glasses, and a field archaeologist's perpetual tan. Twenty years ago, after earning his doctorate at the University of Arizona, he joined Desert Archaeology, Inc., a contract archaeology company in Tucson. He's now a principal investigator for the firm.
In 1997 he began an excavation at Sunset Crater, a volcano near Flagstaff, 125 miles southeast of here. As he dug he turned up a surprising trail of clues in rocks, plants, tree rings, and the ancient memories of Hopi clans. “In archaeology, there's always an unknown,” Elson says. “You always find different things than you expected, and you need to keep adjusting.” To interpret them he entered into an unprecedented collaboration with volcanologists, tree ring specialists, ceramic experts, and Native Americans. The results challenge ideas accepted for decades and have led to proof that volcanoes played a greater role in this region than anyone had imagined. 
Volcanoes have thundered for  millions of years in Northern Arizona, coughing up showers of hot black ash and rivers of molten rock. They've melted snow, set forests ablaze, and spilled sheets of black basalt across the desert. Their lava flows have dammed the Grand Canyon to form immense lakes, and then unleashed huge floods when they collapsed. The state's tallest peak, San Francisco Mountain, is the shattered remnant of a once far taller volcano that may have exploded 400,000 years ago, and it sits surrounded by more than 600 cinder cones. In the summer monsoon when the thunderheads boil and lightning stabs the ground, the volcanoes' silhouettes crowd the horizon like a herd of great, dark beasts. 
Fifteen miles from Flagstaff, Arizona, a one thousand-foot cone stands out. Named for the rosy cinders that tint its summit, Sunset Crater sprang to life centuries ago and has been intriguing ancient Americans, modern archaeologists, geologists, and tourists ever since. Explorer scientist John Wesley Powell named the peak in 1885. “From a distance,” he wrote, “the red cinders seem to be on fire.” In 1928 a Hollywood movie company wanted to fake an eruption and explode the peak with dynamite. Harold S. Colton, Flagstaff's pioneering and most influential archaeologist, came to the mountain's rescue and successfully lobbied to have it declared a National Monument.
In the early 1990s the Arizona Department of Transportation (ADOT) made plans to widen and straighten Route 89, the long, sinuous, and until then, dangerous highway which links Sunset Crater to Phoenix and the Grand Canyon. But the proposed construction would chew through a zone rich with remnants of Arizona's pre-historic past. The 16.6-mile right-of-way was 800 feet wide in places; even a casual walk along it revealed shallow, rock-ringed depressions that marked ancient dwellings and pieces of pottery in full view on the ground.
In 1997 ADOT hired Desert Archaeology to investigate the threatened area. Under Elson's direction, it evolved into one of the most ambitious and comprehensive studies ever undertaken in the region. For ten months between 1997 and 2000, Elson's crew of 25 mapped, surveyed, and collected nearly 100,000 artifacts at 41 sites. They trenched down into pit houses, unearthed masonry rooms, plazas, and burial sites, and excavated or recorded 190 structures.
US 89 climbs almost two thousand feet from the Painted Desert's parched red sandstone to the pine forests in Sunset Crater's cinder fields. It crosses an arid land poor in streams and springs, of porous stone so dry that the Spanish explorers called the highlands Sierra Sin Agua, or “Mountains without Water.”
“Sinagua” is also the name that Harold Colton gave to the area's prehistoric people in the late 1920s. The Sinagua arrived in about 500 AD, and for more than six hundred years lived in small clusters of pit houses -  circular or squarish huts with sunken floors, stone or wood-lined walls, and adobe roofs. They inhabited what Elson calls “the very fringes of survivability,” a narrow zone between 6,200 and 7,200 feet above sea level, where a ninety-day growing season and twenty inches of annual rainfall barely kept their modest fields of corn and beans alive.
The Sinagua's home on the Colorado Plateau lay between two powerful societies. To the northeast were the Anasazi, builders of Chaco Canyon, with its multi-story great houses and sophisticated road network. To the south were the Hohokam, who engineered hundreds of miles of canals to water their desert fields. 
But after about 1100 AD, as these other groups began to collapse, the Sinagua underwent a startling transformation. Many moved down hill almost a thousand feet, from the cinder cones' cool slopes to the sunbaked desert. There they built dramatic multi-story stone pueblos with ball courts and community rooms. Most impressive are the haunting red sandstone pueblos at Wupatki National Monument, whose entrance lies just outside the US 89 project area.
In the 1930s, Colton excavated Sinagua pit houses buried in Sunset Crater's ash, and he attributed the Sinagua's abrupt metamorphosis to the volcano. There were no agonized skeletons nor abandoned objects, and he surmised that pre-eruption earthquakes alerted the Sinagua and enabled their escape. But the eruption spread a blanket of cinders over hundreds of square miles. This ash, Colton said, acted as a mulch that captured rainfall, slowed evaporation, and turned the desert north of the volcano into fertile, moist farmland. Newcomers flocked to this promising unoccupied territory, migrants in a land rush who brought new ideas and building techniques to the Sinagua.
Over the next forty years new population estimates and two findings that established the eruption's beginning and duration helped cast doubt over Colton's narrative. In 1958, dendrochronologist Terah Smiley spotted decades of stunted annual growth rings in Wupatki Pueblo's ancient wooden beams; he said the volcano must have erupted in 1064, when the tree's stressful years began. And in 1977, volcanologists used geophysical evidence to put the eruption's length at two hundred years.
In 1979, Peter Pilles, now chief archaeologist for the Coconino National Forest, proposed that a long, two-century eruption precluded a sudden Sunset Crater land rush. In fact, he said, the population growth had been modest and coincided with a regional population surge engendered by a wetter global climate. The long-simmering volcano may have displaced the Sinagua from time to time, but the changing environment was a far bigger influence.
So, as Elson began, his task seemed clear. He would be studying the Sinagua's adaptation to a changing environment at dozens of sites, built at varying elevations, and occupied over centuries.
But during Elson's first field season, his team found a puzzling layer of volcanic ash directly under a pueblo floor. “We needed to determine the context of these cinders,” says Elson. Were they a volcanic deposit, swept in by wind or water, or had the Sinagua put them there to provide a level base for the house?
Elson called Michael Ort, a volcanologist at Flagstaff's Northern Arizona University. Ort, 42, is a thin, bearded man with an enamel earring, unflagging energy, and a deep knowledge of Sunset Crater. He takes his students there on field trips, and on weekends he bicycles for miles through its black ash fields.
Fresh volcanic ash grains are jagged and fragile, but when the wind bounces them along the ground, it blunts their sharp corners and mixes in dirt. Ort found these ancient cinders to be clean and sharp. This ash, Ort declared, fell directly from the volcano, and soon after the Sinagua built the pueblo atop it.
The more Elson's crews dug, the more fresh ash they found. That was no surprise -the sites were three to eleven miles from the crater. But as he dated the structures, Elson saw that the Sinagua had hurriedly built and occupied most of the sites in a concentrated period of time. Moreover, fields of gritty, abrasive black volcanic ash are uncomfortable places to live. Why, Elson wondered, if the eruption lasted for 200 years, had so many Sinagua suddenly flocked there?
Ort's involvement marked the first time that a volcanologist had worked steadily with archaeologists at Sunset. And the more that he and Elson studied the mountain, the more the conventional wisdom lost its allure.
Sunset Crater is a classic cinder cone, a type of volcano that erupts only once, builds its cone with a steady shower of ash, and bleeds lava from vents at its base. And, Ort points out, the average cinder cone eruption lasts about eight months - most are far shorter. 1040 and 1100.
To better understand what Sunset Crater's clues were telling them, Elson and Ort turned to a contemporary analogue -- Parícutin, the fabled cinder cone that burst into life in a Michoacan, Mexico cornfield in 1943. Parícutin's nine-year tantrum is one of the longest cinder cone eruptions on record. Its lava and ash smothered towns, forests, and farmland. It displaced thousands, sparked fighting between villages, and chased workers north into the United States for jobs. Ort and Wendell Duffield, a retired United States Geological Survey volcanologist, created a scenario for Sunset Crater's eruption based on research at both volcanoes.
Earthquakes came first - small, barely perceptible tremors that grew more frequent and powerful until hundreds a day shook the ground. Suddenly, with a whistle and a roar the earth cracked and blasted blistering black rock into the sky. The crack stretched into an eight mile fissure, slicing across forests and corn fields and spewing a curtain of liquid orange fire that pulsed up to 2,000 feet high. As the Sinagua fled, the roaring vent built a cone with remarkable speed, while a roiling plume of ash and steam punched high beyond the clouds, dropping a rain of choking black dust and blotting out the sun.
The cone quickly grew hundreds of feet tall. Lightning snapped about its summit. At least eight sustained eruptive bursts echoed across the mountains, spitting cinders and volcanic bombs, burying pit houses, fields, and pine trees halfway up their trunks. The cone ruptured, and two tongues of lava, in places ninety feet thick, oozed through the smoking forest. When the volcano sputtered its last, it was close to 1,000 feet tall, and its lava lobes covered three square miles.
A computer model that Elson commissioned shows the eruption plume was visible for at least 250 miles, from high spots in present day California, Nevada, and Colorado, and as far south as Mexico. The night sky in much of central and northern Arizona revealed the lava fountains' golden glow. Says Elson, “It must have been the most awe-inspiring thing these people had ever seen.”
It was also catastrophic. Ort and graduate student Jason Hooten mapped ash dumped over nearly 900 square miles, in places 15 feet thick. And the Sinagua lost more than their homes. An experiment by botanist Gwendolyn Waring showed that corn in the Sunset Crater area will not grow in more than six inches of cinders; the volcano buried about 100 square miles of the Sinagua's prime farmland under more than ten inches of ash.
At least 2,000 people, and probably many more, had to flee, Elson says. Some escaped south into existing communities, but others found new farmland in the lower, warmer arid grasslands to the north. There, as Colton had suggested, the two-to-four inch cinder blanket lay deep enough to retain moisture. And there was plenty of rain. As part of the project, University of Arizona dendroclimatologist Matthew Salzer analyzed the region's ancient tree rings and discovered decades of wet weather following the migration. Some years later a wave of outsiders may have arrived, Elson says, who introduced the Sinagua to new ceramic styles and large pueblos.
Not everyone accepts Elson's findings. Flagstaff archaeologist Peter Pilles feels Elson gives the volcano too much credit. “Obviously a volcanic eruption right in the middle of where people are living is going to be a big deal at the local level,” says Pilles. He still maintains the eruption lasted for 200 years, and that climate change prompted the Sinagua to move to the lowlands. Their adoption of pueblo architecture stemmed from their long experience in masonry building, he says, and new ceramic styles came to them thanks to a regional cultural florescence that spread new ideas throughout the Southwest.
Elson's team is developing a new technique to pinpoint the date and put the debate to rest.
But perhaps the most compelling evidence of sudden catastrophe lives on in the tribal memories of the Hopi, native Americans who are direct descendents of the prehistoric Sinagua. Thirty-four Hopi clans inhabit tall mesas north of Flagstaff, in villages that look across the Painted Desert to the San Francisco Peaks and Sunset Crater. This realm is the dwelling place of hundreds of deities and katsinas, the spirit guardians who act as messengers to the gods.
In his book Black Sand, Harold Colton noted that the Hopi call Sunset Crater Palatsmo, “the red hill.” The cool winds that blow from cracks in the Palatsmo lava flows are the breath of Yaponcha, the wind god, who is trapped inside, and the Hopi leave offerings in an ice cave at the mountain's base. The Qa'na katsina, bringer of corn, dwells at Sunset Crater, and the Hopi say one can see a line of Qa'na katsina dancers in the small pines tossing in the wind along its rim.
Hopi from ten villages worked on the excavations, examined newly unearthed artifacts, and led the researchers along some of the ancient trails that wind from the mesas to Wupatki. And Elson asked anthropologists T. J. Ferguson and Micah Loma'omvaya, a member of the Hopi Bear Clan, to explore how the Hopi perceive the land and their place in it.
The time of u'wing pangk yama - “when fire came forth” - is still a strong presence in Hopi rituals and traditions. “Long ago the ground trembled, a big black smoke came,” a Bear Clan member told the team, and earthquakes heralded a “big fire that came out of the ground.” Ash, lightning, windstorms, and explosions drove some ancestors from their pueblos into smaller dwellings. They dispersed north to the Grand Canyon, west to the high desert, and northeast to the mesa village of Songoopavi.
The Hopi say that Qa'na katsina made Palatsmo erupt because their ancestors were engaged in koyaanisqatsi, or life that is morally imbalanced and corrupt. In their 1987 book Earth Fire, Ekkehart Malotki and Michael Lomatuway'ma relate a Hopi legend of a young girl from the village of Musangnuvi who weds the Qa'na katsina but is later hoodwinked into infidelity by a disguised villager. The outraged katsina takes revenge by inflicting the Sunset Crater eruption, drought, and famine on the village.
But within the punishing eruption lay a kernel of life. When the evil villagers die off, Qa'na katsina brings their survivors sustenance. “He gave each of them a single ear of corn, which they put in their store rooms,” Elson says, “and overnight the corn magically multiplied.” 
The link between Sunset Crater, Hopi, Sinagua, and corn is more than myth. In 1998, at a small pit house settlement two and a half miles from the nearest Sunset Crater lava flow, Elson and his team found 55 chunks of black Sunset Crater lava marked with molded impressions of prehistoric corn. Someone had carried more than 85 pounds of rock to the site, then broke them open to expose the molds.
Elson believes the rocks show that the Sinagua tried to appease the volcano with their most sacred possession, just as people the world over try to stave off flowing lava with saints, charms, statues, and prayers. “Corn was the mainstay of pueblo life,” Elson says, for it provided the bulk of their food. Today's Hopi still use corn cobs as offerings and scatter corn meal in ceremonies, and Sunset Crater's Qa'na katsina is traditionally depicted wearing a bandolier of cobs. Elson says the corn rocks were made intentionally, and not when lava flowed over a cultivated field. Almost all of the cobs were husked but not matured, and some rocks bear impressions of three different corn varieties which would have been planted in separate fields to prevent cross pollination. 
In 1999 Elson, Ort, and Duffield tried and failed to make their own corn rocks by placing cobs in lava flowing from Kilauea volcano in Hawaii.They could duplicate the rocks only by flinging the lava onto the cobs. 
The experiment convinced them that the corn rocks, and the sherd rocks from Little Springs, were made at an `hornito,' a cone of spattered lava that builds up around holes atop crusted-over tubes of flowing lava. Last spring I followed Ort across the Sunset Crater slopes, crunching over ash fields into a ponderosa pine forest where an `hornito' stood like piled up Play-Doh. Elson and Ort think that someone put corn on the lip of a similar hornito to be covered with lava, then later broke off the cooled stone chunks and carried them back to their village.
These rocks were perhaps charms against more than just the eruption. The volcano exploded at a time when the Southwest's primary political powers were in collapse. In the south, the dominant Hohokam system was shrinking, and in the northeast, Chaco Canyon, which had dominated the northern Southwest for centuries, was slipping from power. These upheavals, Elson thinks, may be indirectly rooted in the frightening orange fire fountains, visible to so many. “If social systems had been weakened prior to the eruption, perhaps due to several years of drought or even minor social unrest, the eruption could have been seen as a big time sign that change was in order.”
Back at Little Springs Volcano, Terry Samples identifies the last of the sherds, and our work at the rock ruin is over. Anderson puts away the surveyor's kit, Samples scatters the pottery back on the ground, Elson carefully wraps the sherd rocks in paper and stows them in our truck. The temperature is well past 90°.
For over seventy years, Sunset Crater was thought to be the only active volcano known to the Southwest's prehistoric inhabitants. But the sherd rocks have changed all that.
Little Springs is a junior version of Sunset Crater - at 330 feet high it's one third Sunset's size, and its two lava flows are comparably smaller. But recent paleomagnetic dates put the Little Springs eruption to sometime between 200 and 1200 AD. And the sherds in the melted rock are Hurricane Black-on-Gray, a type datable to 1050-1250 AD. If Little Springs and Sunset Crater did not erupt at the exact same time, they still may have erupted within the life spans of many local people. 
But the two eruptions had vastly different impacts. That afternoon we climbed onto one of Little Spring's twenty-foot high flows to survey its surface. What we found was astonishing. There were hundreds of mysterious features atop the flow. Low semicircular stone walls hugged its edges, and cobbled trails crisscrossed its sun-drenched surface. The trails, smooth enough to run on, wound through twisted, upreared slabs and across carefully bridged crevices. 
The black sea of jumbled rock was baking hot in the Arizona sun, and its abrasive chunks chewed up our boots and, when we fell, shredded our skin. But for hours we followed the flow, marveling at the trails and structures. Aside from two large pieces of pottery, we found no artifacts or other signs of habitation, and we concluded that these sites had a martial function, as holding pens for prisoners, hiding places, or unassailable outposts for archers. Ort says steam from the hot rock deep beneath the flow would have risen for decades, shrouding the warriors and allowing them to emerge and fade like spirits.
When the sun was highest we lay along the ground, reveling in the cool, damp breeze that wafted through holes in the rock, as if the Hopi wind god Yaponcha was trapped, here, too. As we walked I couldn't help but think about those who had sculpted this volcanic slag heap, how they had traveled these trails in their fiber sandals, how their lives required more tenacity and strength than we could ever imagine.
Later, as the sun turned golden, we were still on the flow, searching for a spring described years ago in a previous survey. We found it seeping from the flow into a cement catchment which the Bureau of Land Management built years ago as a watering hole for game. A small rock dam lay a few yards away, erected perhaps a thousand years before to do the very same thing. A trail beside the dam coursed to the top of the flow. Elson and Anderson climbed up and disappeared. I rested a few minutes, then followed.  
The trail snaked over the flow for a hundred yards, to three chest-high circular stone walls more than twenty-five feet in diameter. They were the biggest structures we had seen that day and were perched like forts on a rise overlooking a gulley. In one direction the gulley wound toward the volcano and, in the other, disappeared toward the spring. I found Elson and Anderson down in the gully, sitting beneath a small Gambel oak, beside a smattering of green plants and a shallow six-foot cave. Oddly, cool air filled the hollow. They beckoned me to come down and take a look.
I descended to the cave. Inside was the spring's source: a sheltered mass of solid ice, cold and hard in the 90 degree heat.
Here, Elson says, where rainfall was rare and unpredictable, water sources like the springs and ice caves were coveted, fought over, worshipped, and prized.
 When Little Springs erupted it may have temporarily scattered all who lived here, but unlike the Sinagua, they came back. For them, the flow was a source of refuge and water, a seat of power in a troubled time.
 “Our research is far from complete, but it shows that at Sunset Crater and Little Springs Volcano the local populations not only dealt with the eruptions, but appear to have thrived,” says Elson. “The human capacity for adaptation is nothing short of amazing.”

Copyright © 2004 Tom Gidwitz